A methodological approach to assess the small mammal community diversity in the temperate rainforest of Patagonia

Abstract

Assessingsmallmammaldiversityisacommonprocedure,whichusuallyemployswidespreadstandardtechniques, for gatheringinformationforawiderangeofstudies.Traditionalmethods,however,maybebiasedagainstcapturing arborealmarsupials,suchas Dromiciopsgliroides, anendemicmarsupialcurrentlyconsideredararespeciesinthe Patagoniantemperaterainforestduetothelowabundancesreportedpreviously.Itestedanewcapturingmethodology to assessthesmallmammaldiversityofanold-growthforestinPatagonia,basedonarandomizedandbalanced design, whichincorporatedacombinationofdifferenttraptypes,baittypes,andplacementheights.Theproposed methodologyincludedfourtraptypes(twoforlive-capturing:wire-meshandShermantraps,andtwosign-recording traps fortracksandhair),twotypesofbait(bananaandrolledoats),andtwotrapplacements(groundleveland 1.5–2.5mabovetheground).Traptype,baittype,andheightofplacementallhadsignificantlydifferenteffectson capturinganddetectingrodentsormarsupials;environmentalvariablesatthetraplocationalsoaffectedtheabilityto detect rodentsandmarsupials.Traditionalmethodsusedforsamplingsmallmammalsperformedwellforrodentsbut are noteffectiveforcapturingmarsupialsandviceversa,showingspecies-specificsamplingprotocols.Thereisno singlecombinationoftrap-bait-heightcapabletoassesstheentiresmallmammalcommunity,butthecombinationof the mosteffectiveprotocolforrodentsandthemosteffectiveprotocolformarsupialsguaranteebetterresults. r 2009 DeutscheGesellschaftfu¨r Sa¨ugetierkunde.